In a plasma deposition process, the desired deposition of material on a target in a plasma chamber may be controlled by setting the amount of delivered energy used in the deposition process. To control the delivered energy, a controller controls the output power from the power stage to the plasma chamber based on a power setting. The power setting is a control input set by the user of the equipment to deliver the energy needed to complete the deposition process during the deposition period.
A problem arises in that the actual energy delivered to the plasma chamber varies and does not match the energy called for by the power setting. Further, the variation in actual energy delivered is not a repeatable function so it is not possible to simply preprogram the delivery of more desired energy to compensate for the reduced actual energy delivered. One cause of variations in actual energy delivered is arcing within the plasma chamber. A single arc and its arc recovery interval may last only microseconds. However, there may be several thousand arcs occurring within a second. As a result the actual delivered energy can be 5%-10% lower than the desired energy programmed for delivery in the deposition process over the deposition period.